[Gvsig_english] Projecting EPSG 27700 British National Grid to overlay EPSG 4326 (WGS 1984)

[liam391]

Hi Mario,

Hi Mario,

I created the view in WGS84, and added the raster. I then added the shp
using EPSG 27700, and said yes to the "do you want to re-project" pop-up.
However, the imported shp still does not overly the raster. I think it is a
problem with the raster, as the latitude/long. values make sense for the
reprojected shp, but not fro the raster.

I don't know if the projection info., from "raster properties" would help:

Projection
  PROJCS["Mercator",     GEOGCS["WGS 84",       DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.2572235630016,
          AUTHORITY["EPSG","7030"]],         AUTHORITY["EPSG","6326"]],
      PRIMEM["Greenwich",0],       UNIT["degree",0.0174532925199433],
      AUTHORITY["EPSG","4326"]],     PROJECTION["Mercator_1SP"],
    PARAMETER["central_meridian",0],     PARAMETER["scale_factor",1],
    PARAMETER["false_easting",0],     PARAMETER["false_northing",0],
    UNIT["metre",1,       AUTHORITY["EPSG","9001"]]],

Re the error - If I create the view in EPSG 27700, then add the raster and
try to reproject, GvSig crashes. I could not find the file in the bin
folder, but I did a print screen of the error msg which pops up:
http://osgeo-org.1803224.n2.nabble.com/file/n6207258/GVsigerrormsg.png 

Thankyou
Liam



Hi Liam,

reprojecting on the fly must work correctly. You can create a view in 
EPSG 4326 (geographic coords, WGS84), and load the raster file. Then you 
load the shp file selecting EPSG 27700 for its current system, and it 
will notice you that it will be reprojected on the fly. After loading 
the layer, if you go to the Layer->Export to->SHP menu, you will have 
the shp file in 4326. Do you say that it doesn't work?

About the raster reprojecting, if gvSIG crashes, there's a file whose 
name starts by "hs_err....." in the "bin" folder of your
gvSIG 
installation folder. The date will be the same than the crash time. 
Could you attach it to check what could happen?

Best regards,
   Mario



liam391 escribió:
> Hello,
>
> I am a novice student user of GvSig having used it for basic mapping
and
> geoprocessing for about a year.
>
> I have Raster files in WGS 1984 coordinate system (from Seazone) and I
wish
> to overlay them with shapefiles in EPSG 27700 British National Grid
(these
> are from SNH natural spaces and are available free
>
http://gateway.snh.gov.uk/pls/htmldb_ddtdb1/f?p=101:1:7172302134011178865).
>
> I have tried to use the reproject tool on the shapefiles but so far I
have
> found that either no transformation is available, or GvSig has crashed
when
> I have tried to perform one. Projecting on the fly does not seem to
work;
> attempting to reproject the raster to match the view projection causes
a
> crash and error message. I am running GvSig 1.10 on windows 64 bit.
>
> I apologise for the basic question, but haven't found a solution that
I've
> understood when looking through the forums,
>
> Thanks
>
> Liam
>
&


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